1. Field of the Invention
The invention relates to a ballasted tub for washing machines, in particular clothes washing machines or combined clothes washing and drying machines, said tub being designed in a structurally rigid way and being provided with a quick and simple system for fastening the various ballast masses in position.
2. Description of the Prior Art
Washing machines provided with ballast masses applied to the wash tub in different manners are known from the prior art.
According to one of these prior art embodiments shown, for example, in German Patent 1,186,413, the ballast is formed by a previously prepared concrete block or masses of heavy material of any suitable kind, which are fixed to the front wall of the tub of the washing machine by removable fastening means such as screws, bolts, nuts, washers and the like.
In all these cases, however, the presence of several fastening means of various kinds makes such a ballast mounting complicated in its design and construction and leads to difficulties and inconveniences in assembling the tub.
According to another prior art embodiment, the ballast comprises a molded plastic flange forming the front wall of the tub and being in the shape of a continuous grooved ring having a U-shaped cross-section profile, which is adapted to accommodate a concrete mass, said flange being further provided with a plurality of radial ribs formed on it corresponding to the open front surface of the same flange, so as to retain in its seat the concrete mass that is poured into the cavities resulting between said continuous ring and the respective radial ribs. The flange with the concrete ballast applied thereby is subsequently applied against the curved edge of the cylindrical mantle of the tub by means of a clamping ring which is fitted into the corresponding perimetric groove of said flange after interposing a sealing gasket therebetween.
In practice, this type of tub design has the drawback of being constructively complicated, due to the need to first manufacture the plastic flange and then cast the concrete in the cavities of the same flange, which further prevents the ballast from being given a modular design so as to generate the possibility of adapting the same ballast to balancing applications in connection with differently shaped and sized washing machine tubs, which can be installed in different types of washing machines.
Furthermore, such concrete masses can undesirably become loose and come off their seats in said molded plastic flange, so that these masses will fall outside the flange itself, due to the effect of both the vibrations generated during the operation of the washing machine and the shrinkage of the concrete inside said seats.